The present invention related to a station and a body assembly system.
In the prior art there are systems and assembly stations for welding automotive vehicle bodies and the like in which programmable robots apply welding spots in formation stations (termed `geometry`) and in subsequent completion stations for finishing.
These systems generally include a plurality of handling pallets each provided with centering pins on which is positioned the lower surface of a preassembled body made up of a series of pressed sheet metal panels. The pallet comprises a series of locking members for holding the body in the predetermined position. Usually the pallet comprises series of reference pins fixed to the pallet structure and on which the body is rested. A handling system supports the pallets and moves them along a line which passes through one or more welding stations.
Each welding station includes a series of programmable robots which perform the welding operations and fixed equipment which hold the members transported on the pallet in position during welding.
One disadvantage of the systems described is that the body is positioned on the pallet to be referred to it accurately. The pallet in turn must be positioned accurately with respect to the fixed equipment. As a result the body is positioned with respect to the fixed equipment indirectly through the pallet structure. The necessity of having to provide very accurate pallet structures involves high costs since the pallets are used in large quantities.
In addition, as the dimensional accuracy of the pallets can vary the body positioning accuracy can vary also. This can influence both the quality of the welding and repeatability with harmful effects on final product quality.
Another disadvantage is that the pallet handling and repositioning devices must be kept in good condition to prevent pallet positioning accuracy variation.
The general purpose of the present invention is to obviate the above mentioned drawbacks by making available an assembly system and stations in which pallet production accuracy would not influence the positioning accuracy of the bodies born on the pallets. In addition a further purpose is to make available an assembly system and stations which would not need accurate pallet or handling system positioning and would allow variability between individual pallets and handling systems. Another purpose is to avoid the need for continuously keeping assembly system components such as the pallet or handling systems in optimal condition to ensure body positioning accuracy in the stations.